Thin film transistor and manufacturing method thereof

Abstract

An OTFT is formed by forming a pair of recesses, one being a groove and another being groove or a hole. A source electrode is formed by filling one of the recesses. A drain electrode is formed by filling the other one of the recesses. A film of organic semiconductor material is formed on the source electrode and the drain electrode and makes electrical contact therewith. A gate insulating film is formed on the film of organic material, and a gate electrode is formed on the gate insulating film. The method of manufacturing the OTFT allows realization of high precision microfabrication of the source electrode and the drain electrode formed on the substrate such as a plastic substrate by an inexpensive process.

1 . A thin film transistor comprising: 
 a substrate;    a source electrode;    a drain electrode;    a film of organic semiconductor material formed on the source electrode and the drain electrode and making electrical contact therewith;    a gate insulating film formed on the film of organic semiconductor material; and    a gate electrode formed on the gate insulating film,    wherein the substrate has a pair of recesses, one recess being a groove and the other recess being another groove or a hole, and    wherein the source electrode occupies one of the recesses and the drain electrode occupies the other of the recesses.    
     
     
         2 . The thin film transistor as claimed in  claim 1 , wherein the substrate is made of a thermoplastic material.  
     
     
         3 . The thin film transistor as claimed in  claim 1 , wherein at least one of the source electrode or the drain electrode extends through the substrate.  
     
     
         4 . The thin film transistor as claimed in  claim 2 , wherein at least one of the source electrode or the drain electrode extends through the substrate.  
     
     
         5 . The thin film transistor as claimed in  claim 1 , wherein one of the source electrode or the drain electrode is formed along an outer periphery of the other of the source or drain electrode with a spacing therebetween.  
     
     
         6 . The thin film transistor as claimed in  claim 2 , wherein one of the source electrode or the drain electrode is formed along an outer periphery of the other of the source or drain electrode with a spacing therebetween.  
     
     
         7 . The thin film transistor as claimed in  claim 3 , wherein one of the source electrode or the drain electrode is formed along an outer periphery of the other of the source or drain electrode with a spacing therebetween.  
     
     
         8 . The thin film transistor as claimed in  claim 4 , wherein one of the source electrode or the drain electrode is formed along an outer periphery of the other of the source or drain electrode with a spacing therebetween.  
     
     
         9 . The thin film transistor as claimed in  claim 1 , wherein one of the source electrode or the drain electrode surrounds the other of the source or drain electrode with a spacing therebetween.  
     
     
         10 . The thin film transistor as claimed in  claim 2 , wherein one of the source electrode or the drain electrode surrounds the other of the source or drain electrode with a spacing therebetween.  
     
     
         11 . The thin film transistor as claimed in  claim 3 , wherein one of the source electrode or the drain electrode surrounds the other of the source or drain electrode with a spacing therebetween.  
     
     
         12 . The thin film transistor as claimed in  claim 4 , wherein one of the source electrode or the drain electrode surrounds the other of the source or drain electrode with a spacing therebetween.  
     
     
         13 . The thin film transistor as claimed in  claim 1 , wherein each of the source and drain electrodes has a comb-shaped structure and is formed opposite to each other so that at least one of the comb teeth of the one electrode is disposed in a spacing between an adjacent pair of comb teeth of the other electrode.  
     
     
         14 . The thin film transistor as claimed in  claim 2 , wherein each of the source and drain electrodes has a comb-shaped structure and is formed opposite to each other so that at least one of the comb teeth of the one electrode is disposed in a spacing between an adjacent pair of comb teeth of the other electrode.  
     
     
         15 . The thin film transistor as claimed in  claim 3 , wherein each of the source and drain electrodes has a comb-shaped structure and is formed opposite to each other so that at least one of the comb teeth of the one electrode is disposed in a spacing between an adjacent pair of comb teeth of the other electrode.  
     
     
         16 . The thin film transistor as claimed in  claim 4 , wherein each of the source and drain electrodes has a comb-shaped structure and is formed opposite to each other so that at least one of the comb teeth of the one electrode is disposed in a spacing between an adjacent pair of comb teeth of the other electrode.  
     
     
         17 . A method of manufacturing a thin film transistor comprising the steps of: 
 providing a substrate;    forming a pair of recesses in the substrate, one recess being a groove and the other recess being another groove or a hole;    forming a source electrode in one of the recesses;    forming a drain electrode in the other of the recesses; and    forming a film of organic semiconductor material, a gate insulating film, and a gate electrode on the substrate with the source and drain electrodes.    
     
     
         18 . The method of manufacturing a thin film transistor as claimed in  claim 17 , wherein the recesses are formed in the substrate by thermal imprinting.  
     
     
         19 . The method of manufacturing a thin film transistor as claimed in  claim 17 , wherein the source and drain electrodes are formed by filling the recesses with one of a solution of an electrically conductive material or a liquid dispersion of an electrically conductive material.  
     
     
         20 . The method of manufacturing a thin film transistor as claimed in  claim 18 , wherein the source and drain electrodes are formed by filling the recesses with one of a solution of an electrically conductive material or a liquid dispersion of an electrically conductive material.